JP4939724B2 - Production method of diesel by medium pressure hydrocracking - Google Patents

Abstract

The invention concerns a process for moderate pressure hydrocracking (i.e., at a hydrogen partial pressure of more than 70 bars and at most 100 bars) with a conversion of at least 80% by volume, of a feed with a T5 temperature in the range 250° C. to 400° C. and a T95 temperature of at most 470° C. (T5 and T95 measured in accordance with ASTM-D2887), to produce a diesel with a 95% distillation point of less than 360° C., a sulphur content of at most 50 ppm and a cetane number of more than 51. The process operates with or without a recycle of the liquid effluent. Highly advantageously, it can be integrated into a refinery layout comprising catalytic cracking. The invention also concerns a unit for carrying out said process.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a medium pressure hydrocracking process for producing high yield and very high quality diesel (fuel for diesel engines, simply referred to throughout this specification as "diesel").
[0002]
The present invention also relates to a method including the hydrocracking method, a catalytic cracking method, and an apparatus used to perform the method.
[0003]
[Prior art]
The oil refining industry must find refinery designs that will be able to adapt to stringent fuel quality regulations that will go into effect in Europe in 2005. The maximum sulfur content in diesel will be at most 50 ppm. The 95% distillation point for diesel (ASTM D-86) (currently 360 ° C.) is probably lower, for example 10 ° C., which means for refineries a 5% reduction in the amount of diesel currently produced. It is also foreseen that the current tolerance of polyaromatic compounds will be halved from the current 11% by weight. The cetane number will also rise above 51, for example from the current value of 51 to 52.
[0004]
At the same time, the demand for diesel is constantly increasing and is expected to increase by about 20% over the next decade.
[0005]
Distilling crude oil is not enough to cover diesel production. Diesel is currently produced by a high pressure hydrocracking process (typically at least 120 bar hydrogen gas partial pressure) and is typically at least about 500 ° C. ₉₅ Heavy materials, which are raw materials with temperature, are processed. Where T ₉₅ Is the temperature at which 95% by volume is obtained by simulated distillation (ASTM-D2887). Heavier compounds break down into lighter compounds, some of which enter the middle distillates (diesel and kerosene) of hydrocracking distillation. Such high pressure methods are customary.
[0006]
[Structure of the invention]
In order to meet the new standards, diesel from crude distillation must be subjected to strong hydrodesulfurization. Moreover, high pressure hydrocracking is an expensive solution. Accordingly, more advantageous solutions have been sought that can be incorporated into existing equipment to optimize the use of existing refinery resources.
[0007]
The method disclosed in this application is capable of producing diesel that meets the 2005 standard directly from a relatively light feed under conditions that are more economical than those used in high pressure hydrocracking, at moderate pressures. A functional hydrocracking process (partial hydrogen gas pressure above 70 bar and at most 100 bar).
[0008]
More precisely, the present invention relates to a process for producing diesel having a 95% distillation point of less than 360 ° C., a sulfur content of at most 50 ppm and a cetane number of greater than 51, said process comprising 250 ° C. to 400 ° C. T in the range ₅ Temperature and T at most 470 ° C ₉₅ Treating a hydrocarbon feedstock having a temperature, said method comprising at least 200 Nl / Nl of H ₂ / Raw material volume ratio and 0.15-7h ^-1 A hydrotreatment with hydrocracking at a temperature of at least 320 ° C. under a hydrogen gas partial pressure of at least 70 bar and at most 100 bar, at a space velocity per hour, and the method comprises at least in volume The liquid effluent, which is carried out at a conversion of 80% and obtained by hydrocracking, is distilled to separate the diesel. Desirably, the distillation residue is recycled to the process after purging.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Raw material, hydrotreating and hydrocracking
The raw material to be treated by the method has a T in the range of 250 ° C to 400 ° C, preferably in the range of 280 ° C to 370 ° C. ₅ Have a point. T ₅ The point represents the temperature at which 5% by volume is obtained by simulated distillation (ASTM-D2887).
[0010]
In general, the raw material has a T in the range of 320-400 ° C. ₅ Have a point. Very advantageously, these feeds are fed into diesel fractions, for example heavy diesel from crude oil distillation at atmospheric pressure (usually at least 280 ° C T ₅ Can be added). This heavy diesel fraction can also be obtained directly in atmospheric residue.
[0011]
This procedure (adding diesel) is particularly advantageous. It treats the heavy portion of the diesel fraction (which contains the most difficult to hydrotreat, nitrogen-containing and sulfur-containing compounds) by hydrotreating followed by medium pressure hydrocracking Make it possible. From that point on, conventional hydroprocessing can be used to process the remaining diesel fraction, which does not require expensive investment.
[0012]
Furthermore, by treating the heavy diesel part in the process of the present invention, the heavy fraction is hydrodesulfurized and at the same time its quality is improved (higher than the cetane number obtained only by high intensity hydroprocessing). Cetane number).
[0013]
The raw materials that can be used are also Ts in the range of at most 470 ° C, preferably 450 ° C, more preferably 390-430 ° C. ₉₅ With temperature. T ₉₅ Represents the 95% temperature obtained by simulated distillation (ASTM-D2887).
[0014]
Materials that may be mentioned are light vacuum distillates, light vacuum fractions of conventional vacuum gas oil (VGO) (eg half of the lighter), heavy atmospheric gas oil (HGO), eg from crude oil distillation, or FCC (Catalytic cracking) A mixture of the raw materials, or a mixture of at least one diesel fraction and the raw materials, which is discharged from the apparatus.
[0015]
The treated hydrocarbon feedstock generally has a sulfur content of 0.2% to 4% by weight and a nitrogen content of 100 to 3500 ppm by weight. Thus, they have an organic nitrogen content (ie nitrogen contained in the organic molecule) of 80 ppm or less, or desirably 50 ppm or less, more desirably 10 ppm or less, and an organic sulfur content (ie contained in the organic molecule). Is generally hydrotreated before hydrocracking to reduce the sulfur) to 200 ppm or less, preferably 50 ppm or less. These hydrotreated raw materials (clean raw materials) can then be subjected to hydrocracking.
[0016]
Generally, hydrotreating conditions are
A pressure of 5 to 25 MPa, preferably with a hydrogen gas partial pressure higher than 70 bar and 100 bar, preferably at least 80 bar or at least 85 bar;
A temperature of at least 320 ° C., generally at least 350 ° C. and at most 450 ° C., usually at most 430 ° C.,
At least 100 Nl / l, usually between 100 and 2000 Nl / l, or 300 to 2000 Nl / l H ₂ / Raw material volume ratio,
・ 0.1-10h ^-1 , Preferably 0.15-7h ^-1 , Advantageously 0.05-4h ^-1 Space velocity per hour,
It is.
[0017]
The conversion achieved in the hydrotreatment is generally at least 10% by volume, and less than 40% of the product boils below 350 ° C.
[0018]
Hydrotreating is carried out in the hydrocracking reactor and in the direction of the feed stream, at least in one bed (bed) before the first hydrocracking catalyst bed, or independently before the hydrocracking reactor. In the reactor. There may or may not be an intermediate separation of the gas regenerated by the hydrotreatment. The first mode (same reactor) without intermediate separation is preferred. The method also includes an implementation step where the hydrotreating is performed in the refinery far upstream of the hydrocracking step. Intermediate processing can also be performed.
[0019]
At least a portion of the clean raw material has the following operating conditions:
A hydrogen gas partial pressure of 70 bar or more, at most 100 bar, preferably at least 80 bar or at least 85 bar;
A temperature of at least 320 ° C., generally at least 350 ° C., at most 450 ° C., usually at most 430 ° C.,
H at least 200 Nl / Nl, usually in the range of 300-2000 Nl / Nl ₂ / Raw material volume ratio,
-Space velocity per hour 0.15-7h ^-1 , Preferably 0.05-4h ^-1 , Under the presence of hydrogen, is contacted with at least one hydrocracking catalyst.
[0020]
The method can function regardless of whether or not the distillation residue (unconverted fraction) of the hydrocracked residue is recycled. If there is a recycle, for example if it is separated from the hydrotreating process, the recycle is directed towards the hydrocracking reactor or the reaction in which hydrotreating and hydrocracking is performed Made for the ingredients that enter the vessel.
[0021]
Under these conditions, for the overall process, the conversion of products boiling below 350 ° C. is at least 80% by volume, more usually at least 90% by volume, or at least 95% by volume. .
[0022]
Hydrotreating catalyst
Conventional catalysts can be used, which include at least one amorphous support and at least one hydrodehydrogenation element (generally at least one element from group VIB and a non-noble metal from group VIII). Elements, and usually at least one element from group VIB and at least one non-noble metal element from group VIII).
[0023]
Very advantageously, the hydroprocessing catalyst comprises at least one hydrodehydrogenation element, optionally selected from the group made by at least one matrix, group VIB and group VIII elements of the periodic table, At least one promoter element deposited on the catalyst and selected from the group consisting of phosphorus, boron and silicon, optionally one element from group VIIA (preferably chlorine, fluorine), and optionally from group VIIB Contains one element (preferably manganese), as well as one element from group VB (preferably niobium).
[0024]
In general, hydroprocessing catalysts include the following:
At least one element (% oxide) from group VIB and non-noble metal group VIII, 5% to 40% by weight,
0 to 20%, preferably 0.1 to 20% of at least one promoter selected from phosphorus, boron, silicon (% oxide), advantageously boron and / or silicon is present, optional The presence of phosphorus,
0-20% of at least one group VIIB element (eg manganese),
0-20% of at least one group VIIA element (eg fluorine, chlorine),
0-60% of at least one VB group element (eg niobium),
0.1-95% of at least one matrix (preferably alumina).
[0025]
Desirably, the catalyst comprises boron and / or silicon as promoter elements, optionally with additional phosphorus as other promoter elements. The boron, silicon and phosphorus content is 0.1-20%, desirably 0.1-15%, more advantageously 0.1-10%.
[0026]
Non-limiting examples of matrices that can be used alone or as a mixture are: alumina, halogenated alumina, silica, silica-alumina, clay (natural clays such as kaolin or bentonite), magnesia, titanium oxide, boron oxide , Zirconia, aluminum phosphate, titanium phosphate, zirconium phosphate, charcoal, aluminate. A matrix, preferably containing alumina, more preferably aluminas such as gamma alumina, is used in a manner known to those skilled in the art.
[0027]
The hydrodehydrogenation function is preferably provided by one metal or one metal compound, preferably selected from non-noble metals Group VIII and VI, preferably selected from molybdenum, tungsten, nickel and cobalt. The Desirably, it is provided by a combination of at least one element from group VIII (Ni, Co) and at least one element from group VIB (Mo, W).
[0028]
This catalyst can advantageously comprise phosphorus. In the prior art, this compound is known to have two advantages over hydrotreating catalysts, namely that it is particularly easy to prepare when injecting nickel and molybdenum solutions, and imparts better hydrogenation activity. Yes.
[0029]
In preferred catalysts, the total concentration of metal oxides from Group VI and Group VIII ranges from 5% to 40% by weight, desirably from 7% to 30% by weight, and Group VIB metals (or metals). And the weight ratio expressed as the ratio of metal oxide between Group VII metals (metals) is preferably in the range of 20 to 1.25, more desirably 10 to 2. Phosphorus pentoxide P ₂ 0 ₅ The concentration of is less than 15% by weight, preferably 10% by weight.
[0030]
More preferred hydrotreating catalysts comprising boron and / or silicon (preferably boron and silicon) generally contain at least one metal selected from the following group as a weight percent relative to the total catalyst weight in the following amounts: Just include:
3% to 60%, preferably 3% to 45%, more preferably 3% to 30% of at least one group VIB metal,
And optionally
0-30%, preferably 0-25%, more preferably 0-20%, optionally at least one Group VIII metal.
[0031]
The catalyst further comprises at least one support selected from the following group in the following amounts:
0 to 99%, advantageously 0.1% to 99%, preferably 10% to 98%, more preferably 15% to 95% of at least one amorphous or low crystallinity Matrix.
[0032]
The catalyst is characterized in that it further comprises:
0.1% to 20%, desirably 0.1% to 15%, more desirably 0.1% to 10% boron, and / or 0.1% to 20%, desirably 0.1% to 15%, more preferably 0.1% to 10% silicon,
And optionally:
0-20%, preferably 0.1-15%, more preferably 0.1-10% phosphorus,
And again, preferably
0-20% by weight, preferably 0.1-15%, more preferably 0.1% -10% of at least one element selected from group VIIA, preferably fluorine.
[0033]
In general, formulations having the following atomic ratios are preferred:
-Group VIII metal / VIB group metal atomic ratio in the range of 0 to 1,
-B / VIB group metal atomic ratio in the range of 0.01 to 3,
A Si / VIB group metal atomic ratio in the range of 0.01 to 1.5,
A P / VIB group metal atomic ratio in the range of 0.01 to 1;
-Group VIIA element / VIB metal atom ratio in the range of 0.01-2.
[0034]
Such catalysts have a higher activity for hydrogenating aromatic hydrocarbons and for hydrodenitrogenation and hydrodesulfurization than catalyst formulations containing no boron and / or silicon, Moreover, it has higher activity and selectivity for hydrocracking than known catalyst formulations. A catalyst comprising boron and silicon is particularly advantageous. Without wishing to be bound by any particular theory, it is believed that the particularly high catalytic activity by boron and silicon is due to the enhancement of the acidity of the catalyst due to the combined presence of boron and silicon in the matrix, which enhances its acidity. Provides both improvements in hydrogenation, hydrodesulfurization and hydrodenitrogenation characteristics, as well as improved hydrocracking activity, compared to catalysts commonly used in hydrorefining and hydroconversion reactions.
[0035]
A preferred catalyst is NiMo and / or NiW on an alumina type catalyst, and NiMo on an alumina type catalyst doped with at least one element selected from the group consisting of phosphorus, boron, silicon and fluorine. And / or on silica-alumina or silica-alumina-titanium oxide doped or not with NiW or at least one element selected from the group consisting of phosphorus, boron, fluorine and silicon NiMo and / or NiW type catalysts.
[0036]
Further particularly advantageous catalysts (particularly with improved activity) for hydroprocessing include partially amorphous Y zeolites described in the hydrocracking catalyst section below.
[0037]
Prior to raw material injection, the catalyst used in the process of the present invention is preferably subjected to a sulfidation treatment in order to at least partially convert the metal species to sulfide before they come into contact with the raw material to be treated. It is done. This sulfurization activation process is well known to those skilled in the art and can be performed in-situ, i.e. in the reactor or ex-situ, using any method described in the literature. It can be carried out.
[0038]
Conventional vulcanization methods well known to those skilled in the art include hydrogen sulfide (pure or in a hydrogen / hydrogen sulfide mixture stream), in the range of 150 ° C. to 800 ° C., preferably 250 ° C. to 600 ° C. And heating in the through-bed (cross-bed) reaction zone.
[0039]
Hydrocracking catalyst
Preferred catalysts comprise at least one Y zeolite, at least one matrix and at least one hydrodehydrogenation function. Optionally, it also includes at least one element selected from boron, phosphorus and silicon, at least one VIIA group element (eg chlorine, fluorine), at least one VIIB element (eg manganese) and at least one kind VB group elements (eg, niobium) can be included.
[0040]
The catalyst comprises at least one porous, ie low crystallinity, mineral oxide type matrix. Non-limiting examples that may be mentioned are alumina, silica, silica-alumina, aluminate, alumina-boron oxide, magnesia, silica-magnesia, zirconia, titanium oxide and clay used alone or as a mixture. .
[0041]
The hydrodehydrogenation function generally comprises at least one element from group VIB (eg molybdenum and / or tungsten) and / or at least one non-noble metal element from group VIII (eg cobalt and // nickel). Preferred catalysts essentially comprise at least one Group VI metal and / or at least one non-noble Group VIII metal, Y zeolite and alumina. Further preferred catalysts essentially comprise nickel, molybdenum, Y zeolite and alumina.
[0042]
The catalyst optionally comprises at least one element selected from the group consisting of boron, silicon and phosphorus. Advantageously, the catalyst optionally has at least one element from group VIIA, desirably chlorine or fluorine, optionally at least one element from group VIIB (eg manganese) and optionally at least from group VB. Contains one kind of element (eg niobium).
[0043]
Boron, silicon and / or phosphorus may be in the matrix or zeolite, or, preferably, deposited on the catalyst and therefore primarily on the matrix. Preferred catalysts contain B and / or Si as promoter elements and are desirably deposited in addition to the phosphorus promoter. The amount introduced is 0.1 to 20% of the catalyst by weight, calculated as oxide.
[0044]
Introduced elements, especially silicon, are mainly on the matrix of the support, but like a transmission electron microscope combined with a castaing microprobe (distribution profile of various elements), X-ray analysis of catalyst components. Or by using electron microprobes to create a distribution map of the elements present in the catalyst.
[0045]
In general, preferred hydrocracking catalysts are advantageously
0.1 to 80% by weight of Y zeolite,
-0.1 to 40% by weight of at least one element from group VIB and group VIII (oxide%),
A 0.1-99.8% matrix (% oxide) by weight,
At least one element (% oxide) selected from the group made by P, B, Si, 0-20% by weight, preferably 0.1-20% by weight,
At least one group VIIA element of 0-20% by weight, preferably 0.1-20% by weight,
At least one group VIIB element of 0-20% by weight, preferably 0.1-20%,
At least one VB group element of 0-60% by weight, preferably 0.1-60%,
including.
[0046]
For silicon, the range of 0-20% only includes added silicon and does not include silicon in the zeolite.
[0047]
Zeolite is optionally a metal element such as a metal from the rare earth series, in particular lanthanum and cerium, or a group VIII noble or non-noble metal element, such as platinum, palladium, ruthenium, rhodium, iridium, iron, and manganese, Doped with other metals such as zinc and magnesium.
[0048]
Various Y zeolites are used.
[0049]
Particularly advantageous HY acidic zeolites are characterized by various specifications:
Total SiO in the range of about 6-70, preferably in the range of about 12-50 ₂ / Al ₂ O ₃ Molar ratio, sodium content less than 0.15% by weight (measured with zeolite calcined at 1100 ° C.), 24.58 × 10 ^-10 m-24.24 × 10 ^-10 m, preferably 24.38 × 10 ^-10 m-24.26 × 10 ^-10 lattice parameters in the range of m, sodium ion take-up capacity of CNa above about 0.85 (as neutralized, then calcined, 100 grams of Na, in grams of Na), about 400 m ² / G or more, preferably 550 m ² Water vapor absorption volume at 25 ° C. for a specific surface area (measured using the BET method) of at least / g, gas partial pressure of 2.6 torr (ie 34.6 MPa) of about 6% or more. Furthermore, advantageously, the zeolite is in the range of 5% to 45% of the total pore volume of the zeolite, desirably in the range of 5% to 40% 20 × 10. ^-10 m-80x10 ^-10 in the pores with diameters in the range of m and in the range of 5% to 45% of the total pore volume of the zeolite, preferably in the range of 5% to 40% ^-10 m or more, generally 1000 × 10 ^-10 It has a pore distribution (measured by physical adsorption of nitrogen) contained in pores having a diameter of less than m. The remainder of the pore volume is 20 × 10 ^-10 It is contained in pores having a diameter of less than m.
[0050]
A preferred catalyst using this type of zeolite is a matrix and a lattice constant in the range of 2.424 nm to 2.455 nm, preferably in the range of 2.426 nm to 2.438 nm, a total SiO of 8 or more. ₂ / Al ₂ O ₃ Molar ratio, atomic ratio (n × M ^{n +} ) / Al amount of alkaline earth metal or alkali metal cation and / or rare earth cation such that Al is less than 0.8, preferably less than 0.5 or 0.1, 400 m ² / G or more, preferably 550 m ² P / P of 0.2 / g, more than 6% by specific surface area and weight measured by BET method ₀ And at least one dealuminated titanium zeolite with a water adsorption volume at 25 ° C. relative to the value, said catalyst also comprising at least one hydrodehydrogenated metal and silicon deposited on the catalyst. Including.
[0051]
In an advantageous implementation of the invention, a catalyst comprising a partially amorphous Y zeolite is used for the hydrocracking.
[0052]
The term “partially amorphous Y zeolite”
I) a peak intensity of less than 0.40, preferably less than about 0.30,
Ii) a crystalline portion that is less than about 60%, desirably less than about 50% (as measured by X-ray diffraction and compared to a standard Y zeolite of sodium type (Na)),
Means a solid with
[0053]
Desirably, the partially amorphous Y zeolite, the solid forming part of the catalyst composition of the present invention, has at least one (preferably all) of the following properties:
Iii) a total Si / Al ratio of 15 or greater, preferably greater than 20 and less than 150; iv) a framework Si / Al greater than or equal to the total Si / Al ^IV ,
V) a pore volume of at least 0.20 ml / g of a solid in which the solid fraction in the range of 8% to 50% is composed of pores with a diameter of at least 5 nm (nanometers), ie 50 mm,
・ Vi) 210-800m ² / G, preferably 250-750m ² / G, preferably 300-600 m ² / G specific surface area.
[0054]
The peak intensity and the crystalline part are measured by X-ray diffraction using a procedure derived from the method of ASTM D3906-97 "Measurement of relative X-ray diffraction intensity of faujasite-type containing materials". A comparison with this method must be made with respect to the general conditions of application of this procedure, in particular the preparation of samples and standards.
[0055]
An electron diffraction pattern consists of characteristic lines emanating from the sample and background crystalline parts, essentially caused by scattering from the amorphous or microcrystalline part of the sample (a weak diffusion signal is May be related to air, sample carrier, etc.). The peak intensity of the zeolite is the electron diffraction pattern (peak + background) in a preset angular zone (KαCu curve, l = 0.154 nm, usually 8 ° to 40 ° -2θ). This peak / (peak + background) ratio, which is the ratio of the area of the zeolite wire (peak) to the total area of) is proportional to the amount of crystalline zeolite in the material. In order to calculate the crystalline part of the Y zeolite sample, the peak intensity of the sample is compared to that of a standard that is considered to be 100% crystalline (eg NaY). The peak intensity of completely crystalline NaY zeolite is about 0.55 to 0.60.
[0056]
The peak intensity of conventional USY zeolite is 0.45-0.55, and its crystalline portion for fully crystalline NaY is 80% -95%. The peak intensity of the solid used in the present invention is less than 0.4, preferably less than 0.35. Thus, the crystalline portion is less than 70%, desirably less than 60%.
[0057]
Partially amorphous zeolites are prepared from commercially available, ie generally Y zeolites with high crystallinity (at least 80%), using commonly used dealumination techniques. More generally, it is possible to start with zeolites having at least 60%, or at least 70% crystalline parts.
[0058]
Y zeolites commonly used in hydrocracking catalysts are made by modifying commercially available Na-Y zeolites. This modification can produce zeolites referred to as stabilized, super-stabilized, or dealuminated. This modification is accomplished by at least one of dealumination techniques such as hydrothermal treatment or acid decomposition. Desirably, this modification is accomplished by combining three operations known in the art: hydrothermal treatment, ion exchange and acid decomposition.
[0059]
Further particularly advantageous zeolites are highly acidic zeolites which are not totally dealuminated.
[0060]
The term “totally not dealuminated” refers to “Zeolite Structure Type Atlas”, W.W. M.M. Meier, D.H. H. Olson and Ch. According to the nomenclature developed in Baerlocher, 4th revised edition, 1996, Elsevier, means Y zeolite (structural type, FAU (faujasite)). The lattice constant of this zeolite may be reduced by extracting aluminum from the structure or framework during preparation. However, since aluminum is not chemically extracted, the total SiO ₂ / Al ₂ 0 ₃ The ratio does not change. Such a totally non-dealuminized zeolite is therefore equivalent to the composition of silicon and aluminum (total SiO ₂ / Al ₂ 0 ₃ Ratio). Other parameter values (SiO ₂ / Al ₂ 0 ₃ Ratio and lattice constant) are given below. This totally non-dealuminized Y zeolite can be in the hydrogen form, or hydrogen can be at least partially with a metal cation, such as an alkaline earth metal and / or atomic number 57-71. Of rare earth metal cations. Desirably, zeolites with low rare earth and alkaline earth elements are also used for the catalyst.
[0061]
Y zeolites that have not been dealuminated as a whole generally have a lattice constant of 2.438 nm or more and a total SiO of less than 8. ₂ / Al ₂ 0 ₃ Ratio, less than 21 and total SiO ₂ / Al ₂ 0 ₃ Framework SiO exceeding the ratio ₂ / Al ₂ 0 ₃ Have a ratio. Zeolite that has not been dealuminated as a whole is treated with a process that does not extract aluminum from the sample (eg steam treatment, SiCl ₄ Etc.).
[0062]
Further types of catalysts advantageous for hydrocracking are: phosphorous-doped alumina-type acidic amorphous oxide matrices, totally non-dealuminized, highly acidic Y zeolites and, optionally, Contains at least one element from group VIIA, in particular fluorine.
[0063]
The present invention is not limited to the preferred Y zeolites cited above, and other types of Y zeolites can be used in the process.
[0064]
Prior to feed injection, the catalysts are subjected to a sulfidation treatment to convert at least some of the metal species to sulfide before they come into contact with the feed to be treated. This sulfurization activation treatment is well known to those skilled in the art and can be used in-situ, ie in the reactor or ex-situ, using any method described in the literature. It can be carried out.
[0065]
Conventional sulfidation methods well known to those skilled in the art can be performed at temperatures ranging from 150 ° C. to 800 ° C., preferably in the presence of hydrogen sulfide (pure or in a hydrogen / hydrogen sulfide mixture stream), preferably 250-600 ° C., generally consisting of warming in a passing bed (crossing bed) reaction zone.
[0066]
When the hydrotreating catalyst and hydrocracking catalyst are in the same reactor or in two reactors without an intermediate separation wall, they are sulfided simultaneously.
[0067]
Product separation
The liquid effluent from the hydrocracking then separates the naphtha fraction, diesel fraction, possibly kerosene fraction (which sometimes contains at least part of the diesel fraction), light LPG gas. To be distilled. In general, a liquid residual oil is preferably recycled to the process after purging.
[0068]
Obviously, hydrogen is also separated from the liquid effluent, which is then stripped before being distilled.
[0069]
Unexpectedly, for the process of the present invention, very high quality diesel that meets the standards is produced, and further processing (severe hydrodesulfurization, hydrogenation, etc ...) to improve its quality is necessary Turned out not to be.
[0070]
This process has a 95 volume% distillation point below 360 ° C. (this distillation point is at most 350 ° C., or even at most 340 ° C.), a sulfur content of at most 50 ppm, generally at most 10 ppm, 52 cetane number, more typically at least 54 cetane number, preferably at most 6%, more usually at most 1% aromatic ring compound content, preferably less than −10 ° C. pour point, preferably Can directly produce diesel with an aromatic content of less than 15% by weight.
[0071]
This process also yields quality kerosene with a smoke point greater than 20 mm, desirably above 22 mm, and a sulfur content of less than 50 ppm, desirably less than 10 ppm. At least a portion of kerosene can optionally be sent to the diesel pool, depending on the operator's requirements.
[0072]
Because of the strengthening of the standards, such diesel quality has since been upgraded while allowing upgrades of “light” refinery feedstocks such as existing gas oils, which must be excessive or subsequently subjected to harsh processing. It is noteworthy that it can be obtained without treatment and for a much lower investment than high pressure hydrocracking.
[0073]
With respect to the yield of middle distillate produced (kerosene + diesel), these are at least 60% by volume, usually at least 65% by volume. Other products made are light LPG gas (at most 10% by weight, more commonly at most 5% by weight) and naphtha (typically at least 20% by weight).
[0074]
Drawing
The method will be briefly described with reference to the drawings.
[0075]
FIG. 1 is a flow sheet showing an embodiment of a medium pressure hydrocracking process. FIG. 2 is a flow sheet showing the prior art. 2B, 2C, 3 and 4 are flow sheets showing the method of the present invention incorporated in the catalytic cracking method.
[0076]
The medium pressure hydrocracking process is shown in FIG. The raw material to be processed enters through line 1. In the figure it is added to the hydrocracked residue recycle through line 2 and hydrogen is added through line 3. It mixes with the recycled hydrogen supplied through line 5 and passes through heat exchanger 4. It is then introduced through a reheater 6 into a medium pressure hydrocracking reactor (or reaction zone) 7 (optionally including an upstream hydrotreating zone (s)).
[0077]
The reactor 7 contains at least one catalyst bed 8 of at least one hydrocracking catalyst. Desirably, it can include at least one hydroprocessing catalyst upstream of the first bed 8. The liquid effluent leaving the reactor through line 9 then passes through a gas / liquid separator 10 which separates hydrogen, and the hydrogen is recycled to hydrocracking reactor 7 via line 5.
[0078]
The separated liquid effluent exiting through line 11 is preferably sent to stripper 12 which separates naphtha and light gas through line 13 and the product effluent exiting through line 14 is at atmospheric pressure. Distilled in the distillation column 15. This arrangement schematically illustrates the distillation mode. Other known arrangements that result in separating the same product are also suitable.
[0079]
This yields diesel that is withdrawn through line 16 and residual oil that is separated from the purge through line 17 and recycled through line 2 to the hydrocracking reactor. Optionally, kerosene is obtained.
[0080]
A product separation zone separates hydrocracked residual oil having a boiling point of at least 535 ° C. and recycles the purged residual oil to a line for purging the residual oil and optionally to the hydrocracking zone or reactor Includes lines to be
[0081]
This figure does not show the compressors and equipment used, which are well known to those skilled in the art.
[0082]
The hydrocracking process described here can advantageously be incorporated into refineries and into catalytic cracking processes (generally FCC: fluidized bed catalytic cracking).
[0083]
This results in a combined method of producing both high quality diesel and naphtha (for gasoline production).
[0084]
The invention also relates to an apparatus for performing the method described above. This device
-T in the range of 250 ° C to 400 ° C ₅ Temperature and T at most 470 ° C ₉₅ A column for distilling hydrocarbon feedstock to separate at least one fraction having temperature;
At least one zone for hydrotreating the raw material or the fraction,
At least one zone for medium pressure hydrocracking of the fractions, the medium pressure is above 70 bar, at most 100 bar,
At least one zone for separating the product in order to obtain a diesel with a 95% distillation point below 360 ° C., a sulfur content of at most 50 ppm and a cetane number of over 51,
including.
[0085]
In a special implementation of the invention shown below, the device is:
A column for atmospheric distillation of the crude material to separate at least naphtha, diesel and atmospheric residue
A vacuum distillation column for treating the atmospheric residue and separating at least one vacuum distillate from the vacuum residue;
In the apparatus, the atmospheric distillation column or the vacuum distillation column has a T in the range of 250 ° C. to 400 ° C. ₅ Temperature and T at most 470 ° C ₉₅ Including at least one line for collecting fractions with temperature,
At least one zone for hydrotreating the fraction, followed by at least one medium pressure hydrocracking zone, and a 95% distillation point below 360 ° C., a sulfur content of at most 50 ppm and 51 or more An apparatus also comprising at least one zone for separating the product to obtain a diesel having a cetane number of
including.
[0086]
For a better understanding of the present invention and its advantages, FIG. 2A illustrates the prior art and FIG. 2B illustrates the present invention. The method of the present invention will be described with reference to the drawings.
[0087]
FIG. 2A shows an existing device. Crude hydrocarbon feedstock (ie, crude oil) that reaches through line 20 is distilled in atmospheric tower 21. One naphtha cut (line 22) (the term “one” in this context means “at least one”), one fuel cut (line 23) and one diesel cut (line 24). To be separated.
[0088]
The atmospheric residue leaving the line 25 is vacuum distilled in a vacuum distillation column 26. The vacuum distillate (line 27) is separated leaving a vacuum residue (line 38).
[0089]
The reduced pressure distillate is sent to a catalytic cracker 28 (generally a fluidized bed) which, among other things, is a naphtha withdrawn through line 29, a highly aromatic diesel type distillate withdrawn through line 30 ( Light cycle oil LCO) and a slurry or residual oil drawn through line 31.
[0090]
Normally, the vacuum residue is processed in a visbreaking device 39, which produces, inter alia, low quality naphtha (line 40) and diesel (line 41). Visbreaking residual oil (line 42) can only be used as fuel, like slurry. Part of the LCO can be used to flow fuel.
[0091]
FIG. 2B shows the method and apparatus of the present invention combining medium pressure hydrocracking and catalytic cracking.
[0092]
The reference numbers in FIG. 2A are used, and the visbreaker is usually present in the device, but is not shown to simplify the diagram.
[0093]
In addition to the elements of the prior art (FIG. 2A), the apparatus of the present invention (FIG. 2B) includes a medium pressure hydrocracker 32 that receives the light fraction from the vacuum distillation process fed through line 33.
[0094]
Device 32 is a medium pressure hydrocracking reactor (s) or zone (s) and, above all, high quality diesel via line 34, naphtha and line 36 via line 35. Associated separation means for separating the hydrocracked residue purge through Typically, device 32 also includes a hydroprocessing zone prior to hydrocracking.
[0095]
At least a portion of the hydrocracking residue can be sent for catalytic cracking (device 28), but this is not essential. Purge from the hydrocracking unit is preferably sent to unit 28.
[0096]
This figure does not show the recycling of purged residual oil to a hydrocracking reactor that also contains a hydrocracking zone or hydrotreating zone. Recycling and transport of purge to the FCC can be accomplished separately or together.
[0097]
Within the context of the process of the present invention, the cut point for the distilled diesel fraction (line 24) during atmospheric distillation is selected by the operator, for example as shown in FIG. 2B with FCC Is done.
[0098]
The atmospheric residue (and thus including at least a portion of the heavy atmospheric gas oil) is vacuum distilled into at least one light fraction (distillate) and at least one heavy fraction (distillate); A vacuum residue remains.
[0099]
The light fraction to be treated by hydrocracking is a T in the range of 250 ° C to 400 ° C. ₅ Temperature and T at most 470 ° C ₉₅ With temperature. It is a light vacuum gas oil (LVGO). The end point is selected by the operator according to the available tower and according to the quality improvement desired for the product. The light fraction is treated by the method of the present invention and has the other characteristics of the hydrocarbon feed described above.
[0100]
In general, this light vacuum distillate treatment by medium pressure hydrocracking is a diesel, regardless of the type of reactor (s) reserved for heavy distillate (s) and residual oil from vacuum distillation. Can be carried out if it is to improve the production and / or quality of the.
[0101]
In a further implementation, instead of separating atmospheric residue into light and heavy fractions by vacuum distillation and sending the light fraction (s) to the hydrocracking process, substantially the same for atmospheric distillation. T ₅ Temperature and T ₉₅ A heavy gas oil fraction with temperature is taken (if the tower type allows it). This mode is shown in FIG. 2C, which is indicated with the same reference numbers as in the previous figure, where the feed for device 32 is atmospheric gas oil supplied through line 37. In this figure, line 33 no longer exists. In this case, the atmospheric residue boiling above the heavy gas oil is distilled under reduced pressure, and the vacuum distillation also produces the residue and at least one vacuum distillate (referred to in this case as a heavy distillate). To do.
[0102]
Vacuum distillation residue (line 38) (it is generally at least 535 ° C., desirably at least 550 ° C. or at least 565 ° C. or even 570 ° C. ₅ Can be subjected to, for example, visbreaking (shown in FIG. 1) or residual hydroconversion or coking.
[0103]
In all cases, a T of at most 470 ° C ₉₅ At least one heavy vacuum distillation fraction located between the light fraction having temperature and the vacuum residue is subjected to catalytic cracking.
[0104]
FIG. 3 shows one apparatus and one method in which the heavy fraction from vacuum distillation subjected to catalytic cracking is subjected to hydroprocessing in zone 43 prior to the cracking. The reference numbers in the previous figure are again shown here.
[0105]
This hydrotreatment prior to FCC is performed in the presence of at least one amorphous catalyst. All conventional hydroprocessing catalysts can be used. Catalysts that may be mentioned are preferably at least one non-noble metal group VIII element (for example Co, Ni) and at least one group VIB element (for example Co, Ni) supported on an alumina or silica-alumina based support. Mo, W). The particularity of this process is the operating conditions: hydrogen gas partial pressure of 25-90 bar, preferably less than 85 bar, or more preferably less than 80 bar, or more preferably less than 70 bar, and 350-450. At 370 to 430 ° C., adjusted to maintain a conversion of preferably at least 10%, desirably 40% or less, preferably 15 to 30% of the product boiling at 350 ° C. or less.
[0106]
This yields naphtha (line 44) and diesel (line 45), but is of medium quality and is intended for use as household fuel or sent to a diesel pool.
[0107]
Next, the hydrotreated effluent is transferred to the catalytic cracking device 28.
[0108]
FIG. 4 is a flow chart for the addition of a heavy diesel fraction to apparatus 32 where medium pressure hydrocracking is performed. In this implementation, in addition to the naphtha fraction (line 22), kerosene fraction (line 23), light LGO diesel fraction (line 46) and heavy diesel fraction HGO (line 47), atmospheric distillate can get. This heavy diesel fraction is sent to unit 32 where it is subjected to hydrocracking and then to medium pressure hydrotreating.
[0109]
The present application describes a method for producing diesel and naphtha, where diesel production is accomplished by a medium pressure hydrocracking process as described above, and naphtha production is obtained essentially by catalytic cracking. Desirably, the hydrocracking purge is sent to a catalytic cracking process.
[0110]
Although we have described preferred embodiments of this type of method, other embodiments and procedures that produce the same results are possible.
[0111]
To illustrate the advantages of the present invention, the inventors have shown that production from existing refining schemes and from existing schemes for producing diesel that meets the 2005 standard, and from the schemes of the present invention. Described below. In the scheme of FIG. 2A (existing standard 2000 scheme) for processing 10 Mt / year of North Sea crude oil, we have:
・ Naphtha 3.17Mt / year
・ Jet fuel 0.73Mt / year
・ Diesel 2.32Mt / year
・ Household fuel 1.5Mt / year
565 ° C. + fuel from residual oil subject to visbreaking: 1.42 Mt / year of 40 cst fuel (diluted with LCO, including slurry),
(Scheme 1).
[0112]
This diesel has a cetane number of 49 and a sulfur content of 2100 ppm. In order to meet the standard, it must be subjected to conventional desulfurization processes.
[0113]
Without changing the refinery scheme, but the diesel quality is in compliance with the 2005 standard (95% point taken at 340 ° C), we have
・ Naphtha 3.32Mt / year,
・ Jet fuel cut 0.82Mt / year,
・ Diesel 2.13Mt / year,
・ Household fuel 1.36Mt / year,
565 ° C + 40 cst fuel from residual oil 1.43 Mt / year,
(Scheme 2).
[0114]
This diesel has a cetane number of only 48 and therefore has to be subjected to extremely severe hydrodesulfurization and hydrogenation that cannot be achieved with existing equipment.
[0115]
Naphthapool is estimated to have a sulfur content of 270 ppm by weight, and subsequent harsh processing is required to reduce it to 10-50 ppm by weight. In order to avoid expensive investment, the naphtha fraction from FCC is treated separately by severe hydrodesulfurization, with the disadvantage of reducing the octane number. Other naphtha fractions (eg, from bisbreakers, crude oil distillation, etc.) are sent to the reforming process, and possibly to the isomerization unit prior to hydroprocessing.
[0116]
Adding the hydrotreating step prior to catalytic cracking to Scheme 2 above (as shown in FIG. 3, but under hydrocracking) produces the following (Scheme 3):
・ Naphtha 3.06Mt / year,
・ Jet fuel 0.84Mt / year,
・ Diesel 2.57Mt / year,
・ Household fuel 1.40Mt / year,
565 ° C + 40 cst fuel from residual oil 1.36 Mt / year
The diesel cetane number remains at about 48. FCC naphtha has a sulfur content of 15 ppm, and in naphthenic pools, the sulfur content can be lowered to values as low as about 5.5 ppm without a substantial decrease in octane number.
[0117]
In the preferred scheme 4 of the present invention involving medium pressure hydrocracking (FIG. 3), we have
・ Naphtha 2.90Mt / year,
・ Jet fuel 0.86Mt / year,
・ Diesel 2.82Mt / year,
・ Household fuel 1.44Mt / year,
40 cst fuel 1.34 Mt / year,
Is obtained (Scheme 4).
[0118]
In this case, vacuum distillation separates light fraction 350-410 ° C., heavy fraction 410-565 ° C. and 565 ° C. + residue.
[0119]
In hydrocracking, the conversion is almost complete (≧ 98%) and H ₂ Consumption is 1.85% by weight, pressure is 90 bar ppH ₂ It is.
[0120]
The resulting diesel is as follows:
95% point 340 ℃
Flash point> 60 ° C
Cetane number 56
Sulfur content <10ppm
Polyaromatic ring content <1% by weight.
[0121]
Comparison of these figures shows the superior quality of the diesel obtained using the scheme of the present invention. This quality has never been produced before.
[0122]
For the same product quality, we saved 50 bar of hydrogen pressure compared to conventional hydrocracking, which significantly reduces costs.
[0123]
In terms of productivity, the amount of product is similar to that of Scheme 3, but contrary to Scheme 2 (existing refinery but meets 2005 standards) Shows the following significant increases:
Diesel + 32.4%
Kerosene 4.9%
The inventors were also able to reduce the 40 cst fuel production (−6.3%) and thus adjust the diesel / naphtha balance towards higher quality diesel while adapting the refinery to market needs. Furthermore, since the FCC unit does not move at full capacity, the operator can very advantageously introduce supplemental feedstock (eg atmospheric residue) that can be processed under the FCC. This addition is preferably made to the raw material entering the vacuum distillation column (dotted line in FIG. 3).
[Brief description of the drawings]
FIG. 1 is a flow sheet showing an embodiment of a medium pressure hydrocracking method.
FIG. 2 is a flow sheet showing the prior art.
FIG. 2B is a flow sheet showing the method of the present invention incorporated in the catalytic cracking method.
FIG. 2C is a flow sheet showing the method of the present invention incorporated in the catalytic cracking method.
FIG. 3 is a flow sheet showing the method of the present invention incorporated in the catalytic cracking method.
FIG. 4 is a flow sheet showing the method of the present invention incorporated in the catalytic cracking method.

Claims (9)

A process for the treatment of a crude hydrocarbon feedstock having a sulfur content of 0.2-0.4 wt% and a nitrogen content of 100-3500 wtppm comprising the following steps:
-Atmospheric distillation of the crude hydrocarbon feedstock to produce at least one naphtha, at least one diesel and atmospheric residue;
-Vacuum distillation of atmospheric residue to separate at least one light distillation fraction, at least one heavy distillation fraction and vacuum residue having a boiling point of at least 535 ° C;
- at least a portion of the water hydride cracking residual oil was optionally added at least one catalytic cracking of heavy distillate fraction,
Treatment of the light distillation fraction to produce diesel having a 95% distillation point of less than -360 ° C, a sulfur content of at most 50 ppm and a cetane number of more than 51, wherein the light distillation fraction is from 250 ° C to Hydrotreating with a T ₅ temperature in the range of 400 ° C. and a T ₉₅ temperature of at most 470 ° C., wherein the treatment yields an effluent having an organic nitrogen content of 10 ppm or less, followed by at least one Y zeolite; Medium pressure hydrocracking with a hydrocracking catalyst comprising at least one matrix and at least one hydrodehydrogenation function, said hydrocracking exceeding 70 bar and at most 100 bar hydrogen in gas partial pressure, at a temperature of at least 320 ° C., when at least 200N l / N l _{H 2} / feed volume ratio and 0.15～7H ^-1 Is performed around the space velocity, it is performed in this process 80% conversion at least volume for conversion of products boiling at 350 ° C. or less, and the liquid effluent obtained by hydrocracking is distilled A process in which diesel is separated from hydrocracked residue having a boiling point of at least 535 ° C. The process of claim 1 wherein atmospheric distillation also produces a heavy atmospheric gas oil fraction, which is treated in the same manner as the light distillation fraction. The process according to claim 1 or 2 , wherein the hydrocracked residual oil is recycled to the process after purging. The process according to any one of claims 1 to 3 , wherein a portion of the hydrocracking residual oil is sent for catalytic cracking . The method according to any one of claims 1 to 4 , wherein the conversion is at least 95% by volume. Before being subjected to catalytic cracking, the heavy vacuum distillate has a conversion of at least 10% by volume and less than 40% at a temperature of 350-430 ° C. under a hydrogen gas partial pressure of 25-90 bar, 350 ° C. is hydrotreated to products boiling below method according to any one of claims 1-5. Vacuum residue is, visbreaking, is subjected to treatment according to the method selected from the group consisting of resid hydroconversion and coking method, method according to any one of claims 1-6. The hydrocarbon raw material to be treated by medium pressure hydrocracking is heavy atmospheric gas oil from atmospheric distillation, and at least one heavy decompression at which atmospheric residual oil boiling above the gas oil is subjected to catalytic cracking The method according to any one of claims 1 to 7 , which is distilled under reduced pressure to produce a distillation fraction and a vacuum residue. The resulting 95% point of the diesel at most 340 ° C., with sulfur content and at least 54 cetane number of 10ppm at most, A method according to any one of claims 1-8.

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